Most modern automotive fuel systems use fuel injectors to deliver fuel to the engine cylinders for combustion. The fuel injectors are mounted on a fuel rail to which fuel is supplied by a pump. The pressure at which the fuel is supplied to the fuel rail must be metered to ensure the proper operation of the fuel injector. Metering is carried out using pressure regulators which control the pressure of the fuel in the system at all engine r.p.m. levels.
Most pressure regulator valves use an upper valve member made of stainless steel or other metallic material and a lower valve member or valve seat fabricated from a stainless steel or other metallic material. When the valve is open, the valve element lifts off the valve seat and may dither, making contact with the valve seat. When the valve closes, the valve element drops onto the valve seat. A high density metallic valve element has the potential to wear the sealing surface of the valve seat, which is also called galling. This wear can be attributed to the valve element impacting the valve seat and galling between the valve element and the valve seat.
Coining is a preferred method of improving the sealing surface on the valve seat. A metallic ball or the valve element is used to coin the metallic valve seat. With this process it is possible for galling to occur during coining. When the Young's Modulus of the valve element and the valve seat are similar, both parts can deform at a similar rate during the coining operation. The result may lead to poor leak performance.
Pressure regulators known in the art also use a valve biasing member biased to a valve seat with a longitudinal flow passage. At low fuel pressures, the valve seat is biased to a closed position to prevent the flow of fuel through the pressure regulator. As fuel pressure builds in the system, the pressure against the valve seat overcomes the biasing force of the valve biasing member, allowing fuel to flow through the valve seat, thereby controlling the fuel pressure in the system.
While such pressure regulators have been proven satisfactory, they require a substantial number of parts. In an ongoing effort to reduce the material and manufacturing costs of fuel pressure regulators as well as decrease poor leak performance there exists a need to develop a fuel pressure regulator that is small in size with fewer parts.
Thus, it is believed that there is a need to provide a pressure regulator to overcome the disadvantages of the known pressure regulator.